The invention deals with a sheet metal heating package for regenerative heat exchangers, comprising a plurality of superimposed metal sheets leaving flow channels free in between the sheets and provided at least partially with profiled, for example, embossed sheets which carry a coating, for instance an enamel layer, for surface protection.
The invention also deals with a method and an apparatus for the manufacture of such profiled areas provided with a surface coating for sheet metal heating packages.
Sheet metal heating packages of this type for regenerative heat exchangers are already known from DE-AS 26 16 816. It is however also already known to provide enamel surface protection for the metal sheets which leave flow channels free in between themselves and are provided at least in part with profiles, for instance embossed ones, for the building of such sheet metal heating packages.
Sheet metal heating packages, made of sheet metal with a coating, especially enamel, for surface protection, are always used in regenerative heat exchangers if these are intended to attain a sufficiently high useful life in spite of corrosion exposure and/or if some cleanliness of the heating surfaces is to be assured in order to avoid fire hazard.
It occurs frequently when packaging profiled metal sheets into sheet metal heating packages, that the edge regions or border edges of adjoining sheets come in contact with each other before the remaining area regions. This entails the disadvantage that the surface coating chips off or spalls in the edge region, so that the surface protection is lost there and thus an increased danger of corrosion is set up.